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result(s) for
"Hegde, Gurumurthy"
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Recent Trends and Progress in Corrosion Inhibitors and Electrochemical Evaluation
by
Bijapur, Kiran
,
De Padova, Paola
,
Molahalli, Vandana
in
Alloys
,
Atmospheric corrosion
,
Biological products
2023
Science and engineering research studies are currently concentrating on synthesizing, designing, producing, and consuming ecologically benign chemical species to replace harmful chemicals. This is due to the increasing demands of conservation knowledge and strict ecological regulations. Numerous environmentally friendly substitutes produced from natural resources, including biopolymers, plant extracts, chemical pharmaceuticals (drugs), and so on, are now frequently used as inhibitors to replace dangerous corrosion inhibitors. Many compounds have been extensively used. A range of methods, including physisorption, chemisorption, barrier protection, thin-film growth, and electrochemical procedures, will be used to provide corrosion resistance. The various kinds of corrosion inhibitors (CIs), the mechanisms underlying inhibition, and the evaluation procedures have all been covered in-depth. This review provides an overview of the relevant literature in which researchers and scientists used different types of CIs, the effect of CIs on metals, and information about designs and mechanisms used to minimize corrosion in a variety of equipment composed of alloys or metals, along with electrochemical evaluation studies. This review will provide scholars with fresh insights to advance the discipline.
Journal Article
Self-activated ‘green’ carbon nanoparticles for symmetric solid-state supercapacitors
by
Bhat, Vinay S
,
Sirimahachai Uraiwan
,
Rujiralai Thitima
in
Activated carbon
,
Electrolytes
,
Flux density
2021
Tuning of porosity and surface properties of nanoparticles especially on carbon-based nanomaterials, adopting a ‘greener’ or self-activation synthesis technique for electrical charge storage, is progressing. Herein, we report the self-activation of Teak wood sawdust in a nitrogen atmosphere at different activation temperatures to synthesize carbon nanoparticles. The activated carbon nanoparticles synthesized at 900 °C exhibits a maximum ~ 360 m2 g−1 surface area with ~ 2 nm average pore size diameter. Five electrolytes viz. KOH, KCl, Na2SO4, NaCl, and H3PO4 are used for studying the supercapacitance nature of the activated carbon nanoparticles in a 3-electrode configuration. A maximum specific capacitance of ~ 208 F g−1 @ 0.25 A g−1 is obtained in 1 M KOH as the electrolyte. Two symmetric supercapacitors, aqueous (1 M KOH) and solid-state (PVA/KOH), are fabricated, and their performance difference is compiled. The solid-state symmetric supercapacitor performs in a wider voltage window (1.7 V) with a superior energy density of 27.1 Wh kg−1 at a power density of 178 W kg−1.
Journal Article
ZnO for performance enhancement of surface plasmon resonance biosensor: a review
by
Mei, Gan Siew
,
Menon, P Susthitha
,
Hegde, Gurumurthy
in
Biomolecules
,
Biosensors
,
Chemical compounds
2020
This paper reviews Kretschmann-based SPR sensor utilizing ZnO thin films and nanostructures for performance enhancement. The advancement in surface plasmon resonance technology relies on low-cost, high sensitivity and high selectivity sensor. Metal oxide has been incorporated in SPR sensor to be used for detection of biological and chemical compounds. ZnO as one of the metal oxides is an attractive material due to its unique physical and optical properties. Numerous techniques for fabrication and characterization of ZnO on SPR gold substrate have been studied. The mechanism for gas and biomolecules detection depends on their interaction with ZnO surface, which is mainly attributed to the high isoelectric point of ZnO. There are several types of ZnO nanostructures which have been employed for SPR application based on the Kretschmann configuration. In future, the thin film and nanostructures of ZnO have potential applications for miniature design, robust, high sensitivity, and low-cost portable type of SPR biosensor to be used for on-site testing in real-time and label-free manner.
Journal Article
Exploring the efficiency of green synthesized silver nanoparticles as photocatalysts for organic dye degradation: unveiling key insights
2024
Silver nanoparticles (AgNPs) have received a lot of interest for their several applications, including their remarkable potential as photocatalysts for organic dye degradation. This research thoroughly investigates the efficacy of ecologically friendly, green-synthesized AgNPs in the treatment of synthetic dye-contaminated wastewater. The synthesis of AgNPs from various biological substrates is investigated, emphasizing their economic viability, significant conductivity, and considerable biocompatibility. The improper disposal of synthetic dyes in wastewater poses severe environmental and health risks due to their non-biodegradable nature and persistent chemical features. In response to this challenge, this review paper investigates the capability of AgNPs to serve as effective photocatalysts for degrading a range of organic dyes commonly found in industrial effluents. Specific dyes, including methyl orange, congo red, nitrophenol, methylene blue, and malachite green, are studied in the context of wastewater treatment, providing insights into the efficacy of AgNPs synthesized from diverse biological sources. The review sheds light on the photocatalytic degradation methods used by green-synthesized AgNPs, shedding light on the transition of these synthetic dyes into less hazardous compounds. It also delves into the toxicity aspect of the AgNPs and its possible remediation from the environment. The ecologically friendly synthesis procedures investigated in this work provide an alternative to traditional methods, highlighting the importance of sustainable technologies in solving modern environmental concerns. Furthermore, a comparative examination of various biological substrates for AgNPs synthesis is presented, evaluating their respective dye degradation efficiencies. This not only helps researchers understand the environmental impact of synthetic dyes, but it also directs them in choosing the best substrates for the production of AgNPs with enhanced photocatalytic activities.
Journal Article
Photoaligned Liquid Crystalline Structures for Photonic Applications
2023
With the advancement of information display technologies, research on liquid crystals is undergoing a tremendous shift to photonic devices. For example, devices and configurations based on liquid crystal materials are being developed for various applications, such as spectroscopy, imaging, and fiber optics. One of the problems behind the development of photonic devices lies in the preparation of patterned surfaces that can provide high resolution. Among all liquid crystal alignment techniques, photoalignment represents a promising non-contact method for the fabrication of patterned surfaces. In this review, we discuss the original research findings on electro-optic effects, which were mainly achieved at the Department of Electronic and Computer Engineering of the Hong Kong University of Science and Technology and the collaborating research laboratories.
Journal Article
SnO2QDs Deposited on GO/PPy-Modified Glassy Carbon Electrode for Efficient Electrochemical Hydrogen Peroxide Sensor
by
Molahalli, Vandana
,
Shetty, Apoorva
,
Hegde, Gurumurthy
in
Carbon
,
Chemical sensors
,
Chemicals
2022
In this present work, we demonstrate an efficient electrochemical sensor for the detection of hydrogen peroxide (H2O2) using a glassy carbon electrode (GCE) modified with a ternary nanocomposite of tin oxide QDs/GO/PPy (SGP2). An in situ chemical oxidative polymerization method was used to create the SGP2 nanocomposite. FTIR, XRD, HR TEM, CV, DPV, and impedance analysis were used to characterize the nanocomposite. The SGP2 nanocomposite modified GCE can be used to create an effective H2O2 electrochemical sensor with high sensitivity and a low detection limit (LOD). With SGP2 modified GCE, the electrochemical detection test for H2O2 was carried out using cyclic voltammetry (CV) and amperometric methods. The SGP2 modified GCE shows improved sensing capabilities, resulting in considerable sensitivity of 11.69 µA mM cm−2 and a very low limit of detection (LOD) of 0.758 µM for a broad linear range of H2O2 concentration from 0.1 mM to 0.8 mM with a correlation coefficient R2 = 0.9886. Additionally, the performance of the SGP2-modified GCE electrode is on par with or nonetheless superior to that of the other functional materials that have been reported for H2O2. As a result, our findings suggest that combining conductive polymer with metal oxide may be a useful method for producing sophisticated and affordable electrochemical sensors.
Journal Article
Biowaste-Derived, Highly Efficient, Reusable Carbon Nanospheres for Speedy Removal of Organic Dyes from Aqueous Solutions
by
Joshi, Jyotsna Clemi
,
Krishnappa, Bhavya
,
Hegde, Gurumurthy
in
Activated carbon
,
Adsorbents
,
Adsorption
2022
The current work explores the adsorptive efficiency of carbon nanospheres (CNSs) derived from oil palm leaves (OPL) that are a source of biowaste. CNSs were synthesized at 400, 600, 800 and 1000 °C, and those obtained at 1000 °C demonstrated maximum removal efficiency of ~91% for malachite green (MG). Physicochemical and microscopic characteristics were analysed by FESEM, TEM, FTIR, Raman, TGA and XPS studies. The presence of surface oxygen sites and the porosity of CNSs synergistically influenced the speed of removal of MG, brilliant green (BG) and Congo red (CR) dyes. With a minimal adsorbent dosage (1 mg) and minimum contact time (10 min), and under different pH conditions, adsorption was efficient and cost-effective (nearly 99, 91 and 88% for BG, MG and CR, respectively). The maximum adsorption capacities of OPL-based CNSs for BG were 500 and 104.16 mg/g for MG and 25.77 mg/g for CR. Adsorption isotherms (Freundlich, Langmuir and Temkin) and kinetics models (pseudo-first-order, pseudo-second-order and Elovich) for the adsorption processes of all three dyes on the CNSs were explored in detail. BG and CR adsorption the Freundlich isotherm best, while MG showed a best fit to the Temkin model. Adsorption kinetics of all three dyes followed a pseudo-second-order model. A reusability study was conducted to evaluate the effectiveness of CNSs in removing the MG dye and showed ~92% efficiency even after several cycles. Highly efficient CNSs with surface oxygen groups and speedy removal of organic dyes within 10 min by CNSs are highlighted in this paper.
Journal Article
Mesoporous carbon nanospheres derived from agro-waste as novel antimicrobial agents against gram-negative bacteria
by
Roy, Partha
,
Saha, Sumana
,
Datta, Sriparna
in
adsorption
,
Agricultural wastes
,
Anti-Bacterial Agents - pharmacology
2021
Porous carbon nanospheres were synthesized from agro-waste garlic peels by a one-pot facile and easy to scale-up pyrolysis method. Surface morphology and structural features of the nanospheres have been studied by field emission scanning electron microscopy, energy-dispersive spectroscopy, X-ray diffraction, and Raman spectroscopy. Fourier transform infrared spectroscopy (FTIR) and N
2
adsorption desorption experiments were explored to detect surface functionality, surface area, and porosity. Average particle diameter of the synthesized nanospheres was 31 ± 6.3 nm and zeta potential of − 25.2 mV ± 1.75 mV. Nanoscale carbon was mesoporous in nature with type IV isotherms, mean pore diameter of 15.2 nm, and total pore volume of 0.032 cm
3
/g. Minimum inhibitory concentration and minimum bactericidal concentration values of carbon nanospheres against
Escherichia coli
are 480 ± 0.5 μg/ml and 495 ± 0.5 μg/ml, respectively. Synthesized nanospheres exhibited gram-selective antimicrobial action against
Escherichia coli
probably linked to membrane deformity due to interaction of nanocarbon with the bacterial membrane. Carbon nanospheres resulting from waste to wealth transformation emerged as promising candidates for antibacterial application.
Graphical abstract
Journal Article
Characterization of MWCNT-PEDOT: PSS Nanocomposite Flexible Thin Film for Piezoresistive Strain Sensing Application
2019
Multiwalled carbon nanotubes (MWCNTs) were synthesized by the reduction of ethyl alcohol with sodium borohydride (NaBH4) under a strong basic solvent with the high concentration of sodium hydroxide (NaOH). Nanocomposites of different concentration of MWCNT dispersed in poly(3,4-ethylene dioxythiophene) polymerized with poly(4-styrene sulfonate) (PEDOT:PSS) were prepared and deposited on a flexible polyethylene terephthalate (PET) polymer substrates by the spin coating method. The thin films were characterized for their nanostructure and subsequently evaluated for their piezoresistive response. The films were subjected to an incremental strain from 0 to 6% at speed of 0.2 mm/min. The nanocomposite thin film with 0.1 wt% of MWCNT exhibits the highest gauge factor of 22.8 at 6% strain as well as the highest conductivity of 13.5 S/m. Hence, the fabricated thin film was found to be suitable for piezoresistive flexible strain sensing applications.
Journal Article